This has definitely been done many times, but usually the primary joke isn't just "wow, this person is incompetent". The punchline is usually something that comes as a result of incompetence, like a researcher failing to wash dishes: SCP-885-J (Researcher Jacobs' Inability To Clean Up After Himself), a personnel member repeatedly stealing food from others: SCP-007-J Unidentified Muffin Creature, and so on. There's a lot of more nuanced versions of this, so it might be hard to just straight-up write about someone who's incompetent with nothing else to the joke.